Seat Belt Tensioner: Description and Operation

SAFETY BELT PRETENSIONERS

The front outboard safety belt retractors use a safely belt pretensioner system. This works in conjunction with the front air bag system mounted in the steering wheel and instrument panel. The pretensioner is a pyrotechnic device that removes excess webbing slack from the safety belt. When the front air bags are deployed, the pretensioners deploys in the front safety belt retractors, removing excess slack from the lap and shoulder safety belt. The pretensioners are activated by the restraints control module (RCM) when the module detects a frontal impact force exceeding a programmed limit. If the vehicle is involved in a collision that results in deployment of the front air bags and safety belt pretensioners, a new driver and passenger seat belt system (including safety belt buckle and pretensioners or safety belt retractor and pretensioners. Safety belt retractors, safety belts, buckles and height adjusters), must be installed.